Sanding mechanism



Nov. 3, 1942.

D. H. BOSTWICK ETAL 2,300,643

SANDING MECHANISM Filed Aug. 16, 1940 y 2 Shee'ts-Sfi'et' 1 WMWMMZZATTORNEY .94 D. H. BbsTwlcK rm 2,300,64

SANDING MECHANISM 7 Filed Aug. 16, 1940 2 Shet's-Sheet 2 Patented Nov.3, 1942 UNITED STATES PATENT O FFIC SANDING MECHANISM Douglas H..Bostwickand Theodore Bode, Port Washington, Wis, assignors to TheWisconsin Chair Company, Port Washington, Wis., a corporationof'Wisconsin Application August 16, 1940, Serial No. 352,832

3 Claims.

The present invention relates ingeneral to improvements in theart ofdressing the surfaces of diverse articles preparatory to the applicationof coatings or to final-finishing thereof, and relates more specificallyto various improvements in the construction and operation .of mechanismfor sanding the surfaces of objects'such as component parts offurniture.

An object of our present invention isto provide improved sandingmechanism which is'simple in=construction, and which 'is also flexibleand highly eflicient in use.

In the manufacture of furniture from wood, it is frequently desirable todress *the various parts by sandpapering the surfaces, preparatory tofinal finishing of such surfaces. While-some ofthese surfaces are fiat,many others-are very irregular, and a great many of the objects areprovided with through openings having compound curves and relativelysharp corners which it is extremely difiicult to dress. Although it hasheretofore been attempted to sandpaper such perforated .or grilledobjects with-the aid of continuous sandpaper belts drivenby .pulleys, itwas only possible with these previous belt sanding machines, to utilizeone stretch of the belt at one time,-and the active surfaceof'thisstretch was always moving in the same direction; so that in order tosecure most effective reversed sanding action on the surfaces, it -'wasnecessary to reverse the object "relative -to .the belt. This procedureentailed considerable loss of time and therefore increasedthe cost ofpro duction, and also prevented most effective-utili- Zation of thesanding belts. whilesome-ofzthe prior sanding assemblages'alsomade-crude provision for removing the dust, sand and wood fiber from thezone of action of the sandpaper, these previous dust removers werealsorelatively inefficient and did not properly protect'the workers; and theprior sanding equipment for .dressing wooden objects has also been quiteobjectionable and unsatisfactory for various other reasons.

It is therefore a more specific object of the present invention toprovide anew and useful sandpapering assemblage, especially adapted todress objects having irregularcurves, sharp corners, and intricategrille work, and whereby such objects may be .quickly,.conveniently. andeffectively sanded without endangering theioperator.

Another specific objectof the invention is :to provide improved sandingapparatus which ..is

durable .in constructiomand readily lnranipulablcr and wherein diversearticles may be efi'iciently dressed at minimum cost.

A further specific object of our invention is to provide an improvedendless abrasive belt type of dressing machine, wherein both stretchesof the belt advancing in opposite directions relative to the work, maybe simultaneously utilized, thereby insuring most efficient sandingaction and complete utilization of the belts.

-An additional specific object of this invention is to provide animproved sanding machine wherein the sand and dust are constantly andcompletely removed from the abrasive zone, and in which the operator ismost effectively protected .against possible injury and inhalation ofdangerous particles.

Another-additional object of our invention is to provide a new andhighly useful method of dressing wooden parts by sanding.

Still anotherspecific object of the present invention is to provide animproved endless belt sanding device, wherein the sanding belts may bequickly and conveniently applied to and removed from the work, and inwhich the 'belts may be most effectively utilized to dress any type ofsurface.

Theseand other specific objects and advantages of our improvement, willbe apparent from the: following detailed description.

A clear conception of the several features 'constituting our presentinvention, and of the mode of constructing and of operatingsandingmechanisms built in accordance with the improvement, may be hadby referring to the drawings accompanying and forming a part of thisspecification wherein like reference characters designate the same orsimilar parts in the various views.

Fig. 1 is a top view of a duplex sanding machine comprising twolaterally adjoining units, the dust removal conduits having been omittedfor the sake of clearness;

Fig. 2 is a side elevation of the mechanism shown in Fig. 1, with'thesanding belt in taut condition, and the dust conduits likewise omitted;

Fig. 3 is a fragmentary side elevation similar to that of Fig. 2,but'showing the sanding belt released of tension;

v Fig. 4 is a perspective view of one of the sanding units in actualoperation, and showing the dust removal conduits; and n Fig. 5 is anenlarged fragmentary front elevation of one of the pivotally suspendedidler pulley carrier :arms.

"While. therinvention :h-as .been shown herein r as being embodied in anelectric motor driven assemblage especially adapted to dress grilledwooden furniture parts, it is not our desire or intent to therebyunnecessarily restrict the scope or utility of the improvement for otherpurposes.

Referring to the drawings, each of the improved sanding mechanismsspecifically shown therein comprises in general a structural main frame1 adapted to be mounted upon a floor 8 or other.

idler pulley 6 journalled in its upper swinging end, in line with thecorresponding driving pulley l3; an abrasive coated belt |'I coactingwith the cooperating pulleys l3, H5; a belt tensioning rod I8 pivotallyattached to the upper swinging end of the arm M by a pin l9, and havingthereon an adjustable collar between which and an ad jacent guide plate2| on the frame 1, a compression spring 22 is interposed; a pivot shaft23 carried by the frame 1 and having thereon a swingable arm 24 which isconnected to the lower end of the adjacent rod l8 by means of a set oflinks 25; a stop collar or sleeve 26 embracing the lower end of the rodl8 between the link 25 and the fixed guide plate 2|; a lever arm 21secured to the pivot shaft 23 laterally adjacent to the arm 24; a footpedal 28 swingably suspended from a bracket 29 supported on the floor 8,and being connected to the lever arm 21 by means of a link 3|]; a blowernozzle 3| carried by the swinging upper end of the arm I4 and beingconnected to an air pressure supply pipe 32 by means of a flexibleconduit 33; and a suction cone or funnel 34 connected to a suitablevacuum zone by means of a duct 35, and being disposed in horizontalalinement with the nozzle 3|.

The frame I may be formed of channel irons, metal plate, piping andstandard pipe flanges, and of any desired shape and size, so as toaccommodate either one or more of the improved sanding units, and whenthe driving motor 9 is operating, the shafts ID are rotatingcontinuously unless the corresponding drives l2 are disconnected so asto make one or more of the units inactive. The driving sheaves l3 arepreferably flanged so as to retain the abrasive belts |1 thereon, butthe driven or idler sheaves l6 are not flanged, being crowned androughened as shown in Fig. 5 in order to permit rapid application andremoval of the belts H. The idler sheaves l6 are moreover of relativelysmall diameter so as to bring the upper and lower stretches of the beltsI! close to each other at the zone of sanding, and these sheaves l6 arepreferably journalled in antifriction or ball bearings 36 carried bystub shafts 31 secured to the swinging upper ends of the tubular arms M.The arms l4 may be formed of standard tubing and pipe fittings, and areswingable about pivots 38 carried. by the floor brackets l5, and thecompressed air ejector nozzles 3| may be secured to the stub shafts 31in any suitable manner. I

The sanding or abrasive belts I! may be of any desired width, being tornor ripped from a relatively wide sheet of stock of continuous bandformation, and these belts I! are formed ofheavy and rather durablefabric having thefab'rasi've material applied to the outer surfacethereof. The belt tensioning mechanism comprising the rod I8, collar 20and spring 22, normally resiliently urges the arm l4 away from the frame1, thereby keeping the belt taut but permitting ready deflection of thebelt stretches. The collar 20 may beadjusted along the rod l8 so as tovary the tension 'of the spring 22 and to thereby vary the tension onthe belt l1, and the stop sleeve 26 coacts with the fixed guide plate 2|so as to definitely limit the swinging movement of the arm I4 away fromthe frame I. The upper end of the sleeve 26 will not ordinarily engagethe stop plate 2|, when the belt I! is in use and one or bothstretchesthereof are deflected by contact with the work, but will thusengage the stop when the belt I! has been released and is stretched tomaximum length.

The foot pedal 28 which serves to release the tension on the belt I1, ispreferably positioned within easy reach of an operator 39 who may beseated upon a chair 48 as illustrated in dot-anddash lines in Fig. 3,and the swinging motion of the-pedal 28 may be'limited by a fixed stop4|. The pedal 28 is normally released as in Fig. 2 so as to permit thespring 22 to tension the belt I1; but when the pedal 28 is depressed asin Fig. 3, the shaft 23 will be rocked or rotated in a clockwisedirection by the lever arm 21, and the arm 24 will exert a pull on thelowerend of the rod l8 through the links 25,thereby compressing the.

spring 22, swinging the arm I 4 forward, and releasing the belt tension.The endless abrasive belt ll may then be freely laterally removed fromthe idler pulley |6-and inserted through a selected opening of a grilledwork-piece 42 being held by the operator 39; after which the belt I! mayagain be applied to the pulley 6 and the arm |4 may be released topermit the belt tensioning spring to become active.

The air nozzle 3lis preferably directed across the active portion of thesanding belt I! between the operator and the work closely adjacent tothe zone of sanding, and the suction funnel 34 hasa relatively largemo'uth'and is adapted to receive all dust, sand and wood fiber removedfrom the sanding zone by the air jet. In order to additionally protectthe operator against flying splinters and other particles, a transparentshield 43 supported on the operator's chest between the-sanding zone andthe operator's face, may also be provided; and the operator's eyes maybe additionally protected by goggles 44. It should be noted that whilethe work-piece 42 is of typical formation, these pieces may be ofdiverse shapes and sizes, and the through openings or holes therein maybe of various sizes and shapes.

During normal operation of the improved sanding mechanism, the operator39 may be seated upon the chair 40, the motor 9 is operating to drivethe shaft l0 and pulley I3, air under pressure is being delivered fromthe pipe 32 through the flexible connection 33 and nozzle 3| across thesanding zone, and this air together with any impurities picked up at thesanding zone is being,

constantly withdrawn from this zone through the funnel 34by suction. Theoperator 39 may remove the belt from the idler pulley l6, at will, andmay insert this belt through selected openings in the work-piece 42 andreapply the same to the pulley I6, in an obvious manner. With the beltI! positioned as shown in Fig. 4, the-operator may freely turn thework-piece 42 and-move the same inany desired direction so corners.

as to cause the outer abrasive surfaces of the belt [1 to dress thesurfaces of the grille work. Since the belt I! is relatively flexibleand may be easily deformed by the application of pressure, sanding ofsharp corners and compound curves is made readily possible. Because ofthe fact that the upper and lower stretches of the belt H are moving inopposite directions, it is also possible for the operator to subject thesurfaces of the work-piece 42 to sanding in either or both directions.Because of non-uniformity of the grain, it is frequently desirable tosubject these surfaces to reverse sanding, and the improved mechanismmakes it readily possible for the operator to thus apply the abrasivesurfaces. When the surface of one opening has been satisfactorilydressed, the operator by utilizing the foot pedal 28 may readily releasethe belt I! for removal thereof to another opening, and all of theseoperations can be quickly and conveniently efiected. The blast of airdelivered from the nozzle 3| and across the path of travel of the beltI! closely adjacent to the sanding zone, insures removal of allimpurities and prevents dust and other debris from reaching theoperators face. In this manner the operator 39 is effectively protectedagainst injury and inhalation of impurities, and when the successivework-pieces 42 are completed they may be piled or stacked upon the floornext to the operator, thereby permitting him to rapidly dress successiveobjects.

From the foregoing detailed description it will be apparent that ourpresent invention provides an improved sanding mechanism which isextremely simple, compact and durable in construction, and which is alsohighly efficient and flexible in normal use. The improved sandingapparatus may be readily adjusted and manipulated and is especiallyadapted to dress objects having irregular curves, sharp corners, andintricate grille work. The dressing operation may be performed withoutin any way endangering the operator, and when the belts I! becomeexcessively worn, they may be readily replaced by new belts. The factthat the upper and lower stretches of the belts I! may be used eitheralone or simultaneously, permits most effective application of thesandpaper to the work, and also permits sanding in either or bothdirections so as to most efiectively dress surfaces having the grainrunning in different directions. The fact that the sandpaper belts [1may be readily deflected both longitudinally and laterally, permits mosteffective sanding of compound curved surfaces and The improved apparatushas proven highly satisfactory and efficient in actual commercial use,and the capacity of the equipment may be increased by arranging th unitsin groups of one or more which may be driven by a common motor 9. Whilethe improved assemblage has been described as being especially adaptedto dress wooden objects, it may of course be used for dressing objectsconstructed of other materials such as fiber compositions, paper or thelike. Applicants improved method comprising the application of abrasivesurfaces traveling in opposite directions, to the interior boundingsurfaces of openings in grille work and the like insures most effectivedressing of relatively rough surfaces having the grain disposed indiverse directions, and has also made it possible to utilize sandingbelts for a longer period and without waste of sanding stock.

It should be understood that it is not desired to limit this inventionto the exact details of construction or to the precise mode ofoperation, herein shown and described, for various modifications withinthe scope of the appended claims may occur to persons skilled in theart.

We claim:

1. Sanding mechanism comprising, a driving pulley rotatable about afixed horizontal axis, an arm pivotally suspended at its lower end sothat its upper end will swing toward and away from said pulley in closeproximity to the horizontal plane of said fixed .axis, a small drivenpulley journalled for rotation in said swinging arm end and beingdisposed a considerable distance laterally of said arm in approximatelythe vertical plane of said driving pulley, an abrasive belt c0- actingwith said pulleys, a nozzle swingable with said arm for delivering a jetof air across said belt in close proximity to said driven pulley, and afixed suction funnel for withdrawing air from said belt in line withsaid air jet and within the range of movement of said swinging arm end.

2. Sanding mechanism comprising, a driving pulley rotatable about-afixed horizontal axis, an arm pivotally suspended at its lower end sothat its upper end will swing toward and away from said pulley incloseproximity to the horizontal plane of said fixed axis, a smalldriven pulley journalled for rotation in said swinging arm end and beingdisposed at considerable distance laterally of said arm in approximatelythe vertical plane of said driving pulley, an abrasive belt c0- actingwith said pulleys, a nozzle carried by and swingable with said arm fordelivering a jet of air from one side across said belt in closeproximity and in fixed relation to said driven pulley, and a stationarysuction funnel disposed on the opposite side of said belt forwithdrawing air from said belt in constant alinement with the air jetand within the range of movement of said swinging arm end.

3. Sanding mechanism comprising, a driving pulley rotatable about afixed horizontal axis, an arm pivotally supported from beneath andremote from said pulley so that its upper end can swing toward and awayfrom the pulley in proximity to the horizontal plane of said fixed axis,a driven pulley carried by the upper arm end a considerable distancelaterally of the arm and in approximately the vertical plane of saiddriving pulley, an abrasive belt coacting with said pulleys, a nozzleswingable with said arm for delivering a jet of air across said beltclose to said driven pulley, and suction means for withdrawing air fromsaid belt in line with said nozzle.

DOUGLAS H. BOSTWICK. THEODORE BODE.

